For the past 12 years David Watts has been a protector of much of Sydney's Aboriginal heritage.

There are middens, where Aborigines ate their meals, shelters, and rock engravings of fish, animals, humans and mythological beings.

Many are up to 8000 years old.

"When you actually tell people that the pyramids are basically made yesterday compared to some of these engravings and stuff that are around, people start getting an appreciation for it," he says.

In all, Watts cares for about 1500 of Sydney's 5500-plus sites.

The Aboriginal Heritage Office at Northbridge, on Sydney's north shore, is a partnership of eight councils - Lane Cove, North Sydney, Ku-ring-gai, Manly, Pittwater, Warringah, Willoughby and Ryde - working to protect Aboriginal sites and educate the community.

It has an army of 70 volunteers, mainly bushwalkers and bush regenerators, who help keep an eye on the sites, most of which are in bushland.

Some, however, are in people's backyards.

"A lot of sites are just in people's backyards that people don't know about," he says.

The office works to trace and map the sites using historical records, and new locations are being discovered all the time.

"The biggest myth is that Aboriginal people can claim your backyard or your homes," Watts says.

"It's a really ridiculous thought.

"Fifteen years I've been working on this side of the harbour - opinions have changed.

"They realise that Aboriginal people and groups can claim vacant Crown land and that's it.

"They realise we are here to do a service for the community and actually hang on to the past records of the (local Aboriginal) people."

Sydney's Aboriginal Heritage Office is the only one of it's kind in Australia.

Watts says he is disappointed more councils around the country haven't taken the initiative to start a similar body.

"When you look at councils - they always have a heritage office who looks after European sites that are 200 years old, which is ridiculous compared to 8000 years in Sydney, and when you look at broader parts of Australia you are looking at up to 70,000 years, some of those sites," he says.

"I think it's ridiculous that councils don't take the initiative like the eight councils here and actually start a heritage office in partnership.

"We have had more interest from overseas about this office than we have in our own country."